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Date:   Tue, 28 Nov 2023 18:31:19 +0100
From:   Peter Zijlstra <peterz@infradead.org>
To:     "Aiqun(Maria) Yu" <quic_aiquny@quicinc.com>
Cc:     Elliot Berman <quic_eberman@quicinc.com>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Pavel Machek <pavel@ucw.cz>, Ingo Molnar <mingo@kernel.org>,
        linux-arm-msm@vger.kernel.org,
        Pavan Kondeti <quic_pkondeti@quicinc.com>,
        linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org,
        Abhijeet Dharmapurikar <quic_adharmap@quicinc.com>
Subject: Re: [PATCH 0/2] freezer,sched: do not restore saved_state of a
 thawed task
Message-ID: <20231128173119.GC3818@noisy.programming.kicks-ass.net>
References: <20231120-freezer-state-multiple-thaws-v1-0-f2e1dd7ce5a2@quicinc.com>
 <a86228f5-c1ae-4afe-87bd-5144633a9601@quicinc.com>
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On Tue, Nov 28, 2023 at 05:12:00PM +0800, Aiqun(Maria) Yu wrote:
> On 11/21/2023 1:36 AM, Elliot Berman wrote:
> > This series applies couple fixes to commit 8f0eed4a78a8 ("freezer,sched:
> > Use saved_state to reduce some spurious wakeups") which was found while
> > testing with legacy cgroup freezer. My original testing was only with
> > system-wide freezer. We found that thaw_task could be called on a task
> > which was already frozen. Prior to commit 8f0eed4a78a8 ("freezer,sched:
> > Use saved_state to reduce some spurious wakeups"), this wasn't an issue
> > as kernel would try to wake up TASK_FROZEN, which wouldn't match the
> > thawed task state, and no harm done to task. After commit 8f0eed4a78a8
> > ("freezer,sched: Use saved_state to reduce some spurious wakeups"), it
> > was possible to overwrite the state of thawed task.
> > 
> > To: Rafael J. Wysocki <rafael@kernel.org>
> > To: Pavel Machek <pavel@ucw.cz>
> > To: Ingo Molnar <mingo@kernel.org>
> > To: Peter Zijlstra (Intel) <peterz@infradead.org>
> > Cc:  <linux-arm-msm@vger.kernel.org>
> > Cc: Pavan Kondeti <quic_pkondeti@quicinc.com>
> > Cc: Aiqun Yu (Maria) <quic_aiquny@quicinc.com>
> > Cc:  <linux-pm@vger.kernel.org>
> > Cc:  <linux-kernel@vger.kernel.org>
> > Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
> Shall we add Fixed tag and Cc: stable@vger.kernel.org ?
> Since it is fixing a stable user thread hung issue.

If you want this routed through urgent, then yes.